P2P: Use neg_freq when re-establish persistent group as GC

P2P: Use neg_freq when re-establish persistent group as GC

When GC receives invitation response and tries to re-establish
connection to a persistent group channels from passive list should
be allowed. A missing check for operation mode triggered reselection
of operating channel from active channels only to happen and thus fail
the connect attempt.

Add a check for operation mode and if GC instead use negotiated
frequency (i.e. GO operating channel from invitation response).

Signed-off-by: Mikael Kanstrup <mikael.kanstrup@sonymobile.com>